The present invention relates to a magnetic disc apparatus and, more particularly, to magnetic disc apparatus which accesses plurality of large capacity successive data, and a disc access method for the magnetic disc apparatus. Further, the invention relates to a recording medium having recorded a program for a disc access control for a magnetic disc apparatus.
In computer systems which perform control and administration of OA apparatuses or industrial apparatuses, accompanying with an increase in handling information data, a large capacity memory has been required for recording those information data. As a large capacity memory device satisfying such requirements, a magnetic disc apparatus employing a magnetic disc as recording medium has been widely used.
By the way, in transmitting files between a magnetic disc apparatus and a host apparatus connected externally of the magnetic disc apparatus, it is a basic operation that the magnetic disc apparatus commences access to the magnetic disc in the magnetic disc apparatus after receiving a command issued from the host apparatus.
When a command and a command parameter are transmitted at the same time from the host apparatus, the magnetic disc apparatus calculates at which position on the magnetic disc the data the host apparatus has required an access physically exists, makes the head seek a track on the magnetic disc in the magnetic disc apparatus according to the calculated result, thereby to perform reading out or writing in from/into the data required by the host apparatus.
Hereinafter, such a magnetic disc apparatus will be described, particularly on the operation thereof with reference to drawings.
FIG. 7 is a diagram illustrating an operation of the magnetic disc apparatus, and particularly, a processing performed on the magnetic disc, when the host apparatus accesses two large capacity successive data located apart from each other in the magnetic disc apparatus at the same time.
In FIG. 7, file (mxe2x88x921)xe2x80x2, m, mxe2x80x2 and m+1constitute a part of large capacity successive data A, and file (nxe2x88x921)xe2x80x2, n, nxe2x80x2 and n+1 constitute a part of large capacity successive data B.
Further, file (mxe2x88x921)xe2x80x2 and file m locate on track M, file mxe2x80x2 and file m+1 locate on track M+1, file (nxe2x88x921) and file n locate on track N, and file nxe2x80x2 and file n+1 locate on track N+1. Each file has the size that is equal to the data length which is handled at one time command by the host apparatus.
While when the host apparatus accesses a large capacity successive data, the host apparatus has only to issue commands for accessing files in chronological order of the successive files, when the host apparatus accesses two large capacity successive data at the same time, the host apparatus has to issue commands for accessing respective files in the large capacity successive data A and commands for accessing respective files in the large capacity successive data B, alternately, at a constant period (band). These commands are shown in FIG. 8.
In this case, as shown in FIG. 8, the magnetic disc apparatus interprets the content of the command each time when it receives the issued command, and calculates the positional information at which physical location the demanded data locates physically on the magnetic disc from the command parameter thereby to carry out accessing to the data on the magnetic disc.
That is, in the magnetic disc apparatus, accessing to the large capacity successive data A and accessing to the large capacity successive data B are carried out alternately and successively.
To be concrete, as shown in FIG. 7, accessing to the magnetic disc is carried out in the order of access 1 to the file m and the file mxe2x80x2, seek 1 for executing access 2 to the file n and the file nxe2x80x2, the access 2 to the file n and the file nxe2x80x2, seek 2 for executing access 3 to the file m+1, the access 3 to the file m+1, seek 3 for executing access 4 to the file n+1, and the access 4 to the file n+1.
However, in the conventional magnetic disc apparatus, though accessing to files respectively constituting each of two large capacity successive data are carried out alternatively, and it is possible to predict a physical location from which accessing to data on the optical disc is started, it is impossible to start accessing to respective files until a command is issued from the host apparatus. In other words, the magnetic disc should arise an idle state in which nothing is performed to the magnetic disc during a period from the completion of an access to a file up to starting of a seek for carrying out an access to next file.
That is, when the host apparatus accesses a plurality of large capacity successive data at the same time, even though there is a high possibility of performing an access to data whose access starting position on the magnetic disc can be predicted, the magnetic disc apparatus stops accessing to the magnetic disc and enters a waiting state (the idle state) after completing the accessing to the file now being processed, and the idle state continues until a next command is received. When receiving the next command, the magnetic disc apparatus interprets the received command, calculates location information from the command parameter, and seeks the track in which data is present, and thereafter, starts accessing to the data.
In this way, when the host apparatus accesses a plurality of large capacity successive data at the same time, there should arise an idle state where no access is performed to the magnetic disc, thereby no improvement in the data transfer efficiency.
The present invention is directed to solve the above described problem, and has for its object to provide a magnetic disc apparatus which does not reduce the data transfer efficiency between the magnetic disc and a buffer memory even when accessing to plural systems of large capacity successive data are carried out, to provide a disc access method for the magnetic disc apparatus, which enables the above-described disc access, and further, to provide a recording medium having recorded a disc access control program for a magnetic disc apparatus.
According to a first aspect of the present invention, there is provided a magnetic disc apparatus which can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and preserves location information indicating physical location on the magnetic disc at which data to be accessed for each of the plural systems locate, and in which apparatus a system preserving the location information starts data accessing to the magnetic disc by employing the location information when the magnetic disc apparatus receives a command issued from the host apparatus.
According to the present invention, while accessing large capacity successive data on a magnetic disc, the time required for interpreting a command after receiving the command can be reduced, as well as the time from the completion of an access to one system to the start of an access to next system can be shortened, thereby the data transmission efficiency is enhanced.
According to a second aspect of the present invention, there is provided a magnetic disc apparatus which can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and seeks a magnetic head employed in data access, to a track on the magnetic disc at which data of a system which is supposed to be accessed by the next command locate, without waiting receiving of the next command when the accessing to the data on the magnetic disc at which the respective system data locate is completed.
According to the present invention, by that a seeking of a magnetic head to a track on which data which is supposed to be accesses next is carried out at the conclusion of access to data, the time from the receiving of a command to the starting of an access to the requested data while accessing a large capacity successive data on a magnetic disc is reduced, thereby the time from the completion of an access to one system to the starting of an access to the next system is shortened and the data transfer efficiency is enhanced.
According to a third aspect of the present invention, there is provided a magnetic disc apparatus which can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and performing data access, to a track on the magnetic disc at which data of a system which is supposed to be accessed by the next command locate, without waiting receiving of the next command when the accessing to the data on the magnetic disc at which the respective system data locate is completed.
According to the present invention, by that the data access is started by seeking a magnetic head to a track on which the data which is supposed to be accessed next exists, the time from the receiving of a command to completing the access of the requested data while accessing a large capacity successive data on a magnetic disc is reduced, thereby the time from the completion of an access to one system to the completion of an access to the next system is shortened and the data transfer efficiency is enhanced.
According to a fourth aspect of the present invention, there is provided a magnetic disc apparatus of the second aspect or the third aspect, which stops seeking of a magnetic head to a track on the magnetic disc, in which the predicted system locates, in a case where a command is issued from the host apparatus and the content of the command is not an access to data of the system that is predicted, during the seeking operation that is being performed in the magnetic disc apparatus before receiving the command from the host apparatus.
According to the present invention, in a case where a command to a supposed system is received during the seeking operation and that command is one which accesses not to the supposed system but to another system, the seeking operation to the supposed system is immediately halted, and it is transited to the interpretation of the received command to initiate an access to the requested system, thereby an increase in the access starting time to the system that is requested by the command even when prediction was erroneously performed.
According to a fifth aspect of the present invention, there is provided a magnetic disc apparatus of the third aspect which stops accessing to the data on the magnetic disc in which the supposed system exists, in a case where a command is issued from the host apparatus and the content of the command is not an access to data of the system that is predicted, during the data accessing that is being performed in the magnetic disc apparatus before receiving the command from the host apparatus.
According to the present invention, in a case where a command to a supposed system is received during the seeking operation and that command is one which accesses not to the supposed system but to another system, the accessing to the supposed system is immediately halted, and it is transited to the interpretation of the received command to initiate an access to the requested system, thereby an increase in the access starting time to the system that is requested by the command is restrained even when prediction was erroneously performed.
According to a sixth aspect of the present invention, there is provided a disc access method for a magnetic disc apparatus which apparatus can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and preserves location information indicating physical location on the magnetic disc at which data to be accessed for each of the plural systems locate, and in which apparatus a system preserving the location information starts data accessing to the magnetic disc by employing the location information when the magnetic disc apparatus receives a command issued from the host apparatus.
According to the present invention, while accessing large capacity successive data on a magnetic disc, the time required for interpreting a command after receiving the command can be reduced, as well as the time from the completion of an access to one system to the start of an access to next system can be shortened, thereby the data transmission efficiency is enhanced.
According to a seventh aspect of the present invention, there is provided a disc access method for magnetic disc apparatus which can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and seeks a magnetic head employed in data access, to a track on the magnetic disc at which data of a system which is supposed to be accessed by the next command locate, without waiting receiving of the next command when the accessing to the data on the magnetic disc at which the respective system data locate.
According to the present invention, by that a seeking of a magnetic head to a track on which data which is supposed to be accesses next exists is carried out at the conclusion of access to data, the time from the receiving of a command to the starting of an access to the requested data while accessing a large capacity successive data on a magnetic disc is reduced, thereby the time from the completion of an access to one system to the starting of an access to the next system is shortened and the data transfer efficiency is enhanced.
According to an eighth aspect of the present invention, there is provided a disc access method for a magnetic disc apparatus which can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and performing data access, to a track on the magnetic disc at which data of a system which is supposed to be accessed by the next command locate, without waiting receiving of the next command when the accessing to the data on the magnetic disc at which the respective system data locate.
According to the present invention, by that the data access is started by seeking a magnetic head to a track on which the data which is supposed to be accessed next exists, the time from the receiving of a command to completing the access of the requested data while accessing a large capacity successive data on a magnetic disc is reduced, thereby the time from the completion of an access to one system to the completion of an access to the next system is shortened and the data transfer efficiency is enhanced.
According to a ninth aspect of the present invention, there is provided a disc access method for a magnetic disc apparatus of the seventh aspect or the eighth aspect, which stops seeking of a magnetic head to a track on the magnetic disc, in which the predicted system locates, in a case where a command is issued from the host apparatus and the content of the command is not an access to data of the system that is predicted, during the seeking operation that is being performed in the magnetic disc apparatus before receiving the command from the host apparatus.
According to the present invention, in a case where a command to a supposed system is received during the seeking operation and that command is one which accesses not to the supposed system but to another system, the seeking operation to the supposed system is immediately halted, and it is transited to the interpretation of the received command to initiate an access to the requested system, thereby an increase in the access starting time to the system that is requested by the command even when prediction was erroneously performed.
According to a tenth aspect of the present invention, there is provided a disc access method for a magnetic disc apparatus of the eighth aspect which stops accessing to the data on the magnetic disc in which the supposed system exists, in a case where a command is issued from the host apparatus and the content of the command is not an access to data of the system that is predicted, during the data accessing that is being performed in the magnetic disc apparatus before receiving the command from the host apparatus.
According to the present invention, in a case where a command to a supposed system is received during the seeking operation and that command is one which accesses not to the supposed system but to another system, the accessing to the supposed system is immediately halted, and it is transited to the interpretation of the received command to initiate an access to the requested system, thereby an increase in the access starting time to the system that is requested by the command even when prediction was erroneously performed.
According to an eleventh aspect of the present invention, there is provided a recording medium having recorded a magnetic disc recording apparatus control program, which has recorded a program concerning a disc access method for a magnetic disc apparatus, which apparatus can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and preserves location information indicating physical location on the magnetic disc at which data to be accessed for each of the plural systems locate, and in which apparatus a system preserving the location information starts data accessing to the magnetic disc by employing the location information when the magnetic disc apparatus receives a command issued from the host apparatus.
According to the present invention, while accessing large capacity successive data on a magnetic disc, the time required for interpreting a command after receiving the command can be reduced, as well as the time from the completion of an access to one system to the start of an access to next system can be shortened, thereby the data transmission efficiency is enhanced.
According to a twelfth aspect of the present invention, there is provided a recording medium having recorded a magnetic disc apparatus control program, which has recorded a program concerning a disc access method for a magnetic disc apparatus, which apparatus can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and seeks a magnetic head employed in data access, to a track on the magnetic disc at which data of a system which is supposed to be accessed by the next command locate, without waiting receiving of the next command when the accessing to the data on the magnetic disc at which the respective system data locate.
According to the present invention, by that a seeking of a magnetic head to a track on which data which is supposed to be accesses next exists is carried out at the conclusion of access to data, the time from the receiving of a command to the starting of an access to the requested data while accessing a large capacity successive data on a magnetic disc is reduced, thereby the time from the completion of an access to one system to the starting of an access to the next system is shortened and the data transfer efficiency is enhanced.
According to a thirteenth aspect of the present invention, there is provided a recording medium having recorded a magnetic disc apparatus control program, which has recorded a program concerning a disc access method for a magnetic disc apparatus, which apparatus can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, wherein when a host apparatus connected externally to the magnetic disc apparatus, performs an access to each of plural systems constituting large capacity successive data, which systems are located apart from each other in the magnetic disc apparatus, the magnetic disc apparatus stores a record of commands at the same time when the host apparatus issues commands for accessing the respective systems to the magnetic disc apparatus, compares a new received command with the stored record of commands to detect continuity of commands against the respective systems every time when it receives a new command issued from the host apparatus, and performing data access, to a track on the magnetic disc at which data of a system which is supposed to be accessed by the next command locate, without waiting receiving of the next command when the accessing to the data on the magnetic disc at which the respective system data locate.
According to the present invention, by that the data access is started by seeking a magnetic head to a track on which the data which is supposed to be accessed next exists, the time from the receiving of a command to completing the access of the requested data while accessing a large capacity successive data on a magnetic disc is reduced, thereby the time from the completion of an access to one system to the completion of an access to the next system is shortened and the data transfer efficiency is enhanced.
According to a fourteenth aspect of the present invention, there is provided a recording medium having recorded a magnetic disc apparatus control program, which has recorded a program concerning a disc access method for a magnetic disc apparatus, of the twelfth aspect or the thirteenth aspect, which stops seeking of a magnetic head to a track on the magnetic disc, in which the predicted system locates, in a case where a command is issued from the host apparatus and the content of the command is not an access to data of the system that is predicted, during the seeking operation that is being performed in the magnetic disc apparatus before receiving the command from the host apparatus.
According to the present invention, in a case where a command to a supposed system is received during the seeking operation and that command is one which accesses not to the supposed system but to another system, the seeking operation to the supposed system is immediately halted, and it is transited to the interpretation of the received command to initiate an access to the requested system, thereby an increase in the access starting time to the system that is requested by the command even when prediction was erroneously performed.
According to a fifteenth aspect of the present invention, there is provided a recording medium having recorded a magnetic disc apparatus control program, which has recorded a program concerning a disc access method for a magnetic disc apparatus, of the thirteenth aspect which stops accessing to the data on the magnetic disc in which the supposed system exists, in a case where a command is issued from the host apparatus and the content of the command is not an access to data of the system that is predicted, during the data accessing that is being performed in the magnetic disc apparatus before receiving the command from the host apparatus.
According to the present invention, in a case where a command to a supposed system is received during the seeking operation and that command is one which accesses not to the supposed system but to another system, the accessing to the supposed system is immediately halted, and it is transited to the interpretation of the received command to initiate an access to the requested system, thereby an increase in the access starting time to the system that is requested by the command even when prediction was erroneously performed.
According to a sixteenth aspect of the present invention, there is provided a magnetic disc apparatus which can read out or write into various kinds of information data by accessing a magnetic disc employed as a recording medium, which comprises: a buffer memory which can store a plurality of data per one command which is transferred between the host apparatus and the magnetic disc apparatus in response to the commands issued from the host apparatus which is connected externally to the magnetic disc apparatus; a read/write control part which performs reading and writing of data from/to the magnetic disc; a command record storing means for storing the record of the command when receiving the command from the host apparatus; a command continuity detecting means for detecting continuity of the received commands from the received commands and the command record in the command record storing means at the receiving of the commands; positional information storing means for storing the positional information indicating the physical position on the magnetic disc at which the data on the magnetic disc exists, to which data the command the continuity of which is detected by the command continuity detecting means accesses; and a control part which performs a seek control to the magnetic head which is used for accessing to the data, and gives a reading instruction and a writing instruction for the data on the magnetic disc to the read/write control part before receiving the command from the host apparatus.
According to the present invention, even for the accesses to the large capacity successive file of plural systems on a magnetic disc, whether the record of commands are stored so that whether the accesses are successive or not is detected, and when the continuity of plural systems are detected, the positional information indicating the physical position on the magnetic disc of the data on the magnetic disc which is accessed for respective systems is held, the system to which next access is requested from the host apparatus is predicted from the command record, and the processing for performing accessing to the data of the predicted system is started before the command is received. Therefore, the time from the completion of an access to one system to the start of an access to the next system is shortened, thereby the data transfer efficiency between the host apparatus and the magnetic disc apparatus is enhanced.